don't print field names in static_show of structs

[JeffBezanson]

We don't use this as the default format for show, so it seems like a pretty spurious (even if rare) reason for a precompile statement not to work. Of course it still won't be 100% right, but is much more likely to work.

fixes #38902

[vtjnash]

This would be a usability regression to me. It also doesn't fix #38902, since it isn't 100% right, though it does some common cases of that.

[JeffBezanson]

Obvious suggestion: only change it for printing precompile statements?

[vtjnash]

Perhaps, though in general this is supposed to be a serializer/deserializer, not a deparse/eval function, so I think precompile just needs to handle these better (FWIW, in contrib/generate_precompile, we are already not calling eval directly but instead are starting to deserialize them, because it is more reliable and addresses some other corner cases)